Effect of Polypropylene and Steel Fibers on Fire Resistance of Ultra High Performance Concrete

Abstract

The main goal of this research is study the effect of polypropylene and steel Fibers on fire resistance of Ultra High Performance Concrete. Different trial mixes were used to obtain the effect of high temperature to different durations in the strength of mixes. The research includes also the use of a recognized manufacturer mineral admixture, steel fibers, polypropylene, quartz sand, superplasticizers and without using any type of aggregates other than the quartz sand. The effect of heating samples to 250 ºC and 500 ºC for 2.5 hours and 5 hours was studied for each mix and comparing the compressive and tensile strength among the mixes. Results obtained showed that adding 0.75% of polypropylenes fibers and 16% of Steel fibers to the concrete mix, improved the fire resistance of the concrete mix by 50% and 150% when the samples exposed to 250 ºC and 500 ºC for 2.5 hours respectively, compared with concrete mix without fibers. More ones, fire resistance was improved by 77% and 153% when the samples exposed to 250 ºC and 500 ºC for 5 hours respectively. Also results obtained showed that adding 16% of steel fibers only to the concrete mix, improved the fire resistance of the concrete by 58% and 85% when the samples exposed to 250 ºC and 500 ºC for 2.5 hours respectively, compared with concrete mixes without fibers. Fire resistance was improved by 57% and 88% when the samples exposed to 250 ºC and 500 ºC for 5 hours, respectively. Also results showed that adding 0.75% of polypropylenes fibers only to the concrete mix, improved the fire resistance of the concrete by 27% and 72% when the samples exposed to 250 ºC and 500 ºC for 2.5 hours respectively, compared with concrete mixes without fibers. In addition, fire resistance was improved by 39% and 14% when the samples exposed to 250 ºC and 500 ºC for 5 hours, respectively.